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Creating a co_await awaitable signal that can be awaited multiple times, part 1--Raymond Chen

By Adrien Hamelin | Mar 3, 2021 02:54 PM | Tags: c++20

Harnessing the power of coroutines.

Creating a co_await awaitable signal that can be awaited multiple times, part 1

by Raymond Chen

From the article:

C++/WinRT asynchronous activities can be awaited only once. This is consistent with their intended usage pattern, which is for an application to start the activity, co_await the result, and then continue.

But maybe you want something like a Win32 event, where any number of people can co_await the event, and then once it is signaled, all the awaiters are resumed...

C++ Concepts: More than Syntactic Requirements--Jonathan Boccara

By Adrien Hamelin | Mar 2, 2021 03:34 PM | Tags: c++20

A new tool to simplify usage.

C++ Concepts: More than Syntactic Requirements

by Jonathan Boccara

From the article:

After years and years of expectation, concepts have finally made it in C++20.

Concepts are descriptions in code of a set of expressions that must be valid with a given type. Those are syntactic requirements. But there is more to concepts than that: concepts also have semantic requirements.

Before getting into that, here is a recap of what concepts are. If you’re already familiar with concepts you can skip to the section on semantic requirements...

My tutorial and take on C++20 coroutines--David Mazières

By Adrien Hamelin | Mar 2, 2021 03:30 PM | Tags: c++20

Detailed and interesting.

My tutorial and take on C++20 coroutines

by David Mazières

From the article:

Over the last 25 years, I’ve written a lot of event-driven code in C++. A typical example of event-driven code is registering a callback that gets invoked every time a socket has data to be read. Once you have read an entire message, possibly after many invocations, you parse the message and invoke another callback from a higher layer of abstraction, and so forth. This kind of code is painful to write because you have to break your code up into a bunch of different functions that, because they are different functions, don’t share local variables...

Next steps for Clang Power Tools--Horatiu Prica

By Adrien Hamelin | Mar 2, 2021 03:24 PM | Tags: community

Were you using them?

Next steps for Clang Power Tools

by Horatiu Prica

From the article:

We are happy to announce that Clang Power Tools is now entirely free for everyone while keeping it open-source on GitHub. We had a blast these past two years, working full-time on making Clang Power Tools better and bringing to fruition its code modernization mission...

Registries: Bring your own libraries to vcpkg--Nicole Mazzuca

By Adrien Hamelin | Mar 1, 2021 02:03 PM | Tags: None

Are you using vcpkg?

Registries: Bring your own libraries to vcpkg

by Nicole Mazzuca

From the article:

Are you working on a C++ project with library dependencies? Are you tired of maintaining a custom-built package management workflow with duct tape and git submodules? Then you should consider trying out a package manager. Perhaps you have been side-eyeing vcpkg for a while, and it looks like the perfect solution for your team, but for one problem: not all your dependencies are open source! Your company has internal libraries that they expect everyone to use too...

2021-02 Mailing Available

By Administrator | Feb 28, 2021 01:53 PM | Tags: None

The 2021-02 mailing of new standards papers is now available.

 

WG21 Number Title Author Document Date Mailing Date Previous Version Subgroup
N4880 PL22.16/WG21 agenda: 22 February 2021, Virtual Meeting John Spicer 2021-01-23 2021-02   All of WG21
N4881 WG21 virtual meetings: 2021-02, -06, and -10 Herb Sutter 2021-02-08 2021-02   All of WG21
N4882 WG21 admin telecon meetings: 2021-02, -05, and -09 Herb Sutter 2021-02-08 2021-02   All of WG21
N4883 WG21 February 2021 admin telecon minutes Nina Ranns 2021-02-16 2021-02   All of WG21
P0401R6 Providing size feedback in the Allocator interface Chris Kennelly 2021-02-15 2021-02 P0401R5 LWG Library
P0448R3 A strstream replacement using span as buffer Peter Sommerlad 2021-02-17 2021-02 P0448R2 LWG Library
P0849R7 auto(x): decay-copy in the language Zhihao Yuan 2021-02-15 2021-02 P0849R6 EWG Evolution,LWG Library
P1018R8 C++ Language Evolution status pandemic edition 2020/11–2021/01 JF Bastien 2021-01-27 2021-02 P1018R7 EWG Evolution,All of WG21
P1072R7 basic_string::resize_and_overwrite Chris Kennelly 2021-02-15 2021-02 P1072R6 LWG Library
P1322R3 Networking TS enhancement to enable custom I/O executors Christopher Kohlhoff 2021-02-14 2021-02 P1322R2 SG4 Networking,LEWG Library Evolution
P1425R3 Iterators pair constructors for stack and queue Corentin Jabot 2021-02-18 2021-02 P1425R2 LEWG Library Evolution,LWG Library
P1659R2 starts_with and ends_with Christopher Di Bella 2021-02-10 2021-02 P1659R1 LWG Library
P1659R3 starts_with and ends_with Christopher Di Bella 2021-02-19 2021-02 P1659R2 LWG Library
P1682R3 std::to_underlying JeanHeyd Meneide 2021-01-22 2021-02 P1682R2 LWG Library
P1885R5 Naming Text Encodings to Demystify Them Corentin Jabot 2021-02-15 2021-02 P1885R4 SG16 Unicode,LEWG Library Evolution
P1951R1 Default Arguments for pair's Forwarding Constructor Logan R. Smith 2021-02-21 2021-02 P1951R0 LWG Library
P2047R1 An allocator-aware optional type Nina Ranns 2021-02-19 2021-02 P2047R0 LEWGI SG18: LEWG Incubator,LEWG Library Evolution
P2066R5 Suggested draft TS for C++ Extensions for Minimal Transactional Memory Jens Maurer 2021-02-14 2021-02 P2066R4 SG1 Concurrency and Parallelism,SG5 Transactional Memory,EWG Evolution,LEWG Library Evolution
P2093R4 Formatted output Victor Zverovich 2021-02-15 2021-02 P2093R3 LEWG Library Evolution
P2128R3 Multidimensional subscript operator Corentin Jabot 2021-02-15 2021-02 P2128R2 EWG Evolution
P2162R2 Inheriting from std::variant (resolving LWG3052) Barry Revzin 2021-02-17 2021-02 P2162R1 LEWG Library Evolution
P2164R4 views::enumerate Corentin Jabot 2021-02-18 2021-02 P2164R3 LEWG Library Evolution
P2195R2 Electronic Straw Polls Bryce Adelstein Lelbach 2021-01-27 2021-02 P2195R1 All of WG21
P2216R3 std::format improvements Victor Zverovich 2021-02-15 2021-02 P2216R2 LWG Library
P2231R1 Add further constexpr support for optional/variant Barry Revzin 2021-02-11 2021-02 P2231R0 LEWG Library Evolution
P2234R1 Consider a UB and IF-NDR Audit Scott Schurr 2021-02-13 2021-02 P2234R0 SG12 Undefined and Unspecified Behavior,EWGI SG17: EWG Incubator
P2242R1 Non-literal variables (and labels and gotos) in constexpr functions Ville Voutilainen 2021-02-14 2021-02 P2242R0 EWG Evolution,CWG Core
P2249R0 Mixed comparisons for smart pointers Giuseppe D'Angelo 2021-01-30 2021-02   LEWGI SG18: LEWG Incubator,LEWG Library Evolution
P2280R1 Using unknown references in constant expressions Barry Revzin 2021-02-15 2021-02 P2280R0 EWG Evolution
P2281R1 Clarifying range adaptor objects Tim Song 2021-02-19 2021-02 P2281R0 LWG Library
P2286R1 Formatting Ranges Barry Revzin 2021-02-19 2021-02 P2286R0 LEWG Library Evolution
P2287R1 Designated-initializers for base classes Barry Revzin 2021-02-15 2021-02 P2287R0 EWG Evolution
P2289R0 2021 Winter Library Evolution Polls Bryce Adelstein Lelbach 2021-01-31 2021-02   LEWG Library Evolution
P2290R0 Delimited escape sequences Corentin Jabot 2021-02-18 2021-02   SG22 Compatability,EWG Evolution
P2291R0 Add Constexpr Modifiers to Functions to_chars and from_chars for Integral Types in Header Daniil Goncharov 2021-01-28 2021-02   LEWGI SG18: LEWG Incubator,LEWG Library Evolution,LWG Library
P2295R0 Correct UTF-8 handling during phase 1 of translation Corentin Jabot 2021-02-15 2021-02   SG16 Unicode,SG22 Compatability,EWG Evolution
P2297R0 Wording improvements for encodings and character sets Corentin Jabot 2021-02-19 2021-02   SG16 Unicode
P2301R0 Add a pmr alias for std::stacktrace Steve Downey 2021-02-15 2021-02   LEWG Library Evolution,LWG Library
P2302R0 Prefer std::ranges::contains over std::basic_string_view::contains Christopher Di Bella 2021-02-10 2021-02   LEWG Library Evolution
P2303R0 Function literals and value closures Jens Gustedt 2021-02-10 2021-02   SG22 Compatability
P2304R0 Improve type generic programming Jens Gustedt 2021-02-10 2021-02   SG22 Compatability
P2305R0 Type inference for variable definitions and function returns Jens Gustedt 2021-02-10 2021-02   SG22 Compatability
P2306R0 Type-generic lambdas Jens Gustedt 2021-02-10 2021-02   SG22 Compatability
P2307R0 Lvalue closures Jens Gustedt 2021-02-10 2021-02   SG22 Compatability
P2309R0 A common C/C++ core specification Jens Gustedt 2021-02-11 2021-02   SG22 Compatability
P2310R0 Revise spelling of keywords Jens Gustedt 2021-02-11 2021-02   SG22 Compatability
P2311R0 Make false and true first-class language features Jens Gustedt 2021-02-11 2021-02   SG22 Compatability
P2312R0 Introduce the nullptr constant Jens Gustedt 2021-02-15 2021-02   SG22 Compatability
P2314R0 Character sets and encodings Jens Maurer 2021-02-12 2021-02   SG16 Unicode,EWG Evolution
P2315R0 C++ Standard Library Issues to be moved in Virtual Plenary, Feb. 2021 Jonathan Wakely 2021-02-12 2021-02   All of WG21
P2316R0 Consistent character literal encoding Corentin Jabot 2021-02-18 2021-02   SG22 Compatability,EWG Evolution
P2317R0 C++ - An Invisible foundation of everything Bjarne Stroustrup 2021-02-14 2021-02   All of WG21
P2320R0 The Syntax of Static Reflection Andrew Sutton 2021-02-15 2021-02   SG7 Reflection
P2321R0 zip Tim Song 2021-02-20 2021-02   LEWG Library Evolution
P2322R0 ranges::fold Barry Revzin 2021-02-18 2021-02   LEWG Library Evolution
P2323R0 maybe_unused attribute for labels Martin Uecker 2021-02-16 2021-02   SG22 Compatability
P2324R0 Labels at the end of compound statements (C compatibility) Martin Uecker 2021-02-16 2021-02   SG22 Compatability
P2325R0 Views should not be required to be default constructible Barry Revzin 2021-02-17 2021-02   LEWG Library Evolution

GotW #100 Solution: Preconditions, part 1 -- Herb Sutter

By Blog Staff | Feb 25, 2021 06:54 PM | Tags: None

Solution just posted:

GotW #100 Solution: Preconditions, Part 1

by Herb Sutter

From the article:

We've seen how postconditions are directly related to assertions (see GotWs #97 and #99). So are preconditions, but that in one important way makes them fundamentally different. What is that? And why would having language support benefit us even more for writing preconditions more than for the other two?